1. Field of the Invention
The present invention relates to a telephoto zoom lens (short zoom lens) for a photographic camera and in particular, it relates to a small and high-performance telephoto zoom lens having a zoom ratio of approximately 4.
2. Description of the Related Art
A telephoto zoom lens is known having a zoom ratio of approximately 3, as disclosed in, for example Japanese Unexamined Patent Publication No. 1-310322, in which three lens groups, i.e., a first positive lens group, a second negative lens group and a third positive lens group are included, wherein the three lens groups are independently moved to carry out the zooming.
However, no compact three-lens group type zoom lens is known having a zoom ratio of approximately 4. Moreover, in the known three-lens group type zoom lens, if the zoom ratio is being around 4, the curvature of the field caused by the zooming is too large to correct.